
$(function(){
	var show_num = [];
	draw(show_num);

	$("#canvas").on('click',function(){
		draw(show_num);
	})
	//1903010226 $(".btn").on('click',function(){
		 $("#submit").on('click',function(){
		var val = $(".input-val").val().toLowerCase();
		var num = show_num.join("");
		if(val == num){
			location('index.php');
			$(".input-val").val('');
		}else{
			$(".input-val").val('');
		}
	})
});

//1903010226生成并渲染出验证码图形
function draw(show_num) {
	var canvas_width=$('#canvas').width();
	var canvas_height=$('#canvas').height();
	var canvas = document.getElementById("canvas");//1903010226获取到canvas的对象，演员
	var context = canvas.getContext("2d");//1903010226获取到canvas画图的环境，演员表演的舞台
	canvas.width = canvas_width;
	canvas.height = canvas_height;
	var sCode = "a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
	var aCode = sCode.split(",");
	var aLength = aCode.length;//1903010226获取到数组的长度
	
	for (var i = 0; i < 4; i++) {  //1903010226这里的for循环可以控制验证码位数（如果想显示6位数，4改成6即可）
		var j = Math.floor(Math.random() * aLength);//1903010226获取到随机的索引值
		//1903010226 var deg = Math.random() * 30 * Math.PI / 180;//1903010226产生0~30之间的随机弧度
		var deg = Math.random() - 0.5; //1903010226产生一个随机弧度
		var txt = aCode[j];//1903010226得到随机的一个内容
		show_num[i] = txt.toLowerCase();
		var x = 10 + i * 20;//1903010226文字在canvas上的x坐标
		var y = 20 + Math.random() * 8;//1903010226文字在canvas上的y坐标
		context.font = "bold 23px 微软雅黑";

		context.translate(x, y);
		context.rotate(deg);

		context.fillStyle = randomColor();
		context.fillText(txt, 0, 0);

		context.rotate(-deg);
		context.translate(-x, -y);
	}
	document.getElementById("canvas").value = show_num.join("");
	for (var i = 0; i <= 5; i++) { //1903010226验证码上显示线条
		context.strokeStyle = randomColor();
		context.beginPath();
		context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
		context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
		context.stroke();
	}
	for (var i = 0; i <= 30; i++) { //1903010226验证码上显示小点
		context.strokeStyle = randomColor();
		context.beginPath();
		var x = Math.random() * canvas_width;
		var y = Math.random() * canvas_height;
		context.moveTo(x, y);
		context.lineTo(x + 1, y + 1);
		context.stroke();
	}
}

//1903010226得到随机的颜色值
function randomColor() {
	var r = Math.floor(Math.random() * 256);
	var g = Math.floor(Math.random() * 256);
	var b = Math.floor(Math.random() * 256);
	return "rgb(" + r + "," + g + "," + b + ")";
}

